Costantini David, Bonisoli-Alquati Andrea, Rubolini Diego, Caprioli Manuela, Ambrosini Roberto, Romano Maria, Saino Nicola
Department of Biology, University of Antwerp, Universiteitsplein 1, 2610, Wilrijk, Belgium,
Naturwissenschaften. 2014 Jul;101(7):541-8. doi: 10.1007/s00114-014-1190-2. Epub 2014 Jun 3.
Reproduction is a demanding activity, since organisms must produce and, in some cases, protect and provision their progeny. Hence, a central tenet of life-history theory predicts that parents have to trade parental care against body maintenance. One physiological cost thought to be particularly important as a modulator of such trade-offs is oxidative stress. However, evidence in favour of the hypothesis of an oxidative cost of reproduction is contradictory. In this study, we manipulated the brood size of wild barn swallows Hirundo rustica soon after hatching of their nestlings to test whether an increase in nestling rearing effort translates into an increased oxidative damage and a decreased antioxidant protection at the end of the nestling rearing period. We found that, while plasma oxidative damage was unaffected by brood size enlargement, females rearing enlarged broods showed a decrease in plasma non-enzymatic antioxidants during the nestling rearing period. This was not the case among females rearing reduced broods and among males assigned to either treatment. Moreover, individuals with higher plasma oxidative damage soon after the brood size manipulation had lower plasma non-enzymatic antioxidants at the end of the nestling rearing period, suggesting that non-enzymatic antioxidants were depleted to buffer the negative effects of high oxidative damage. Our findings point to antioxidant depletion as a potential mechanism mediating the cost of reproduction among female birds.
繁殖是一项要求苛刻的活动，因为生物体必须生育后代，而且在某些情况下，还要保护和养育它们的后代。因此，生活史理论的一个核心原则预测，亲代必须在亲代抚育和身体维持之间进行权衡。一种被认为作为这种权衡调节因素特别重要的生理成本是氧化应激。然而，支持繁殖存在氧化成本这一假说的证据相互矛盾。在本研究中，我们在家燕雏鸟孵化后不久就对其巢中雏鸟数量进行了操控，以测试育雏努力的增加是否会在育雏期结束时转化为更高的氧化损伤以及更低的抗氧化保护能力。我们发现，虽然血浆氧化损伤不受巢中雏鸟数量增加的影响，但养育更多雏鸟的雌性家燕在育雏期间血浆非酶抗氧化剂含量有所下降。养育较少雏鸟的雌性家燕以及接受任何一种处理的雄性家燕则并非如此。此外，在巢中雏鸟数量操控后不久血浆氧化损伤较高的个体，在育雏期结束时血浆非酶抗氧化剂含量较低，这表明非酶抗氧化剂被消耗以缓冲高氧化损伤的负面影响。我们的研究结果表明，抗氧化剂消耗是介导雌鸟繁殖成本的一种潜在机制。
